The Red Sox are through with platooning, position shuffling and roster finagling. Jose Iglesias is now Boston’s everyday starting third baseman.

How many people saw that coming six months ago?

Manager John Farrell‘s decision to option Will Middlebrooks to Triple-A Pawtucket on Tuesday meant that the slick-fielding Iglesias, who came into spring training with serious doubts about his swing and did not play a single professional game at the hot corner until this May, has officially usurped one of the franchise’s rising stars — for the time being, at least.

It’s clear that Iglesias still sees himself as a shortstop (even his Twitter handle, @JoseIglesias_SS, suggests as much). But with Middlebrooks unable to help the team offensively and shortstop Stephen Drew continuing to gradually come around after a slow start, third base is where Iglesias can help the team right now.

He did just that Tuesday night. In his first game since officially taking over full-time, Iglesias went 3-for-5 with a double, an RBI and two runs scored, improving his season average to an astounding .434. That would lead all Red Sox hitters had he enough at-bats to qualify, as would his .484 on-base percentage and 1.059 OPS. It is still not fair to compare his numbers to those of David Ortiz and Dustin Pedroia, who both have more than double the at-bats of Iglesias this season, but it’s difficult to continue the argument that his production is not sustainable.

As starter Ryan Dempster said after Tuesday’s 11-4 drubbing of the Rockies, there’s no such thing as a “soft” .434.

Iglesias went into this past offseason knowing the scouting report on him: a Gold Glove-caliber infielder who can’t hit. Through months of hard work, including time spent training with Pedroia, he has transformed his game, and those around baseball are finally beginning to take notice.

“I went to Arizona, spent time with [Pedroia]. Talking about baseball, talking about discipline on the plate,” Iglesias said. “We talked about not just on the field, but off the field, too. Be consistent, take care of your body, eat healthy, get some rest. Little things that help you play in a long season like this.”

And the demotion is not a career-breaker for Middlebrooks. Farrell hopes starting every day in Triple-A will allow Middlebrooks to get consistent at-bats and rediscover his rhythm, with intentions of him returning to help the big-league club in the future. But the skipper did state, in no uncertain terms, that this is now Iglesias’ position, not a stopgap until Middlebrooks regains his swagger.

“First of all, [Middlebrooks’] skills haven’t gone backwards,” Farrell said in his pregame news conference. “He’s still a very talented player, and the consistent work will allow him to reproduce the swing he showed last year and showed throughout the course of spring training. Recognizing that this year, there were some struggles with him, this isn’t uncommon with young players. And to take a step back now for the bigger picture … he’s finding his way to becoming a major league player, and part of that sometimes takes a step back. That’s exactly what’s taking place.”

There will be a day when Middlebrooks can again contribute for the Red Sox. He’s too talented not to. But until then, third base is Jose Iglesias’ position to lose, and the 23-year-old is showing no signs of letting that happen.